<template>
	<div class="canvas-box" :style="{ height: contentHeight + 'px' }">
		<canvas id="id-canvas" class="id-canvas" :width="contentWidth" :height="contentHeight"></canvas>
	</div>
</template>
 
<script setup lang="ts" name="Identify">
import { onMounted, watch } from "vue";
 
interface IProps {
	identifyCode?: string; // 默认注册码
	fontSizeMin?: number; // 字体最小值
	fontSizeMax?: number; // 字体最大值
	backgroundColorMin?: number; // 验证码图片背景色最小值
	backgroundColorMax?: number; // 验证码图片背景色最小值
	dotColorMin?: number; // 背景干扰点最小值
	dotColorMax?: number; // 背景干扰点最小值
	contentWidth?: number; // 容器宽度
	contentHeight?: number; // 容器高度
}
const props = withDefaults(defineProps<IProps>(), {
	identifyCode: "1234",
	fontSizeMin: 25,
	fontSizeMax: 35,
	backgroundColorMin: 200,
	backgroundColorMax: 220,
	dotColorMin: 60,
	dotColorMax: 120,
	contentWidth: 100,
	contentHeight: 40
});
// 生成一个随机数
const randomNum = (min: number, max: number) => {
	return Math.floor(Math.random() * (max - min) + min);
};
 
// 生成一个随机的颜色
const randomColor = (min: number, max: number) => {
	let r = randomNum(min, max);
	let g = randomNum(min, max);
	let b = randomNum(min, max);
	return "rgb(" + r + "," + g + "," + b + ")";
};
 
const drawPic = () => {
	let canvas = document.getElementById("id-canvas") as HTMLCanvasElement;
	let ctx = canvas.getContext("2d") as CanvasRenderingContext2D;
	ctx.textBaseline = "bottom";
	// 绘制背景
	ctx.fillStyle = "#e6ecfd";
	ctx.fillRect(0, 0, props.contentWidth, props.contentHeight);
	// 绘制文字
	for (let i = 0; i < props.identifyCode.length; i++) {
		drawText(ctx, props.identifyCode[i], i);
	}
	drawLine(ctx);
	drawDot(ctx);
};
 
const drawText = (ctx: CanvasRenderingContext2D, txt: string, i: number) => {
	ctx.fillStyle = randomColor(50, 160); // 随机生成字体颜色
	ctx.font = randomNum(props.fontSizeMin, props.fontSizeMax) + "px SimHei"; // 随机生成字体大小
	let x = (i + 1) * (props.contentWidth / (props.identifyCode.length + 1));
	let y = randomNum(props.fontSizeMax, props.contentHeight - 5);
	const deg = randomNum(-30, 30);
	// 修改坐标原点和旋转角度
	ctx.translate(x, y);
	ctx.rotate((deg * Math.PI) / 180);
	ctx.fillText(txt, 0, 0);
	// 恢复坐标原点和旋转角度
	ctx.rotate((-deg * Math.PI) / 180);
	ctx.translate(-x, -y);
};
 
const drawLine = (ctx: any) => {
	// 绘制干扰线
	for (let i = 0; i < 4; i++) {
		ctx.strokeStyle = randomColor(100, 200);
		ctx.beginPath();
		ctx.moveTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
		ctx.lineTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
		ctx.stroke();
	}
};
 
const drawDot = (ctx: any) => {
	// 绘制干扰点
	for (let i = 0; i < 30; i++) {
		ctx.fillStyle = randomColor(0, 255);
		ctx.beginPath();
		ctx.arc(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight), 1, 0, 2 * Math.PI);
		ctx.fill();
	}
};
 
onMounted(() => {
	drawPic();
});
 
watch(
	() => props.identifyCode,
	val => {
		console.log(val);
		drawPic();
	}
);
</script>
 
<style lang="scss" scoped>
.canvas-box {
	cursor: pointer;
	.id-canvas {
		height: 100%;
	}
}
</style>